Fuel supply system for internalcombustion engines



Feb.'l9, 1952 R. H. D. CHAMBERLIN I ,5 0

FUEL SUPPLY SYSTEM FOR INTERNAL-COMBUSTION ENGINES Filed Sept. 11, 1946 l I nuenlor A llorneyJ.

DETONAN T Patented Feb. 19, 1952 FUEL SUPPLY SYSTEM FOR INTERNAL- COMBUSTION ENGINES Reginald Henry Douglas Chamberlin, London, England, assignor to D. Napier & Son Limited, London, England, a company of Great Britain Application September 11, 1946, Serial No. 696,223 In Great Britain September 11, 1945 9 Claims (arms-119) This invention relates to fuel supply systems for a internal combustion engines and has for its object to provide means for introducing a liquid antidetonant into the fuel being delivered to the engine.

It is known that under certain conditions assointo the engine induction passage, a pump which can deliver a liquid anti-detonant to a point at or adjacent to this fuel intake, a regulator for the pressure at which this anti-detonant is delivered. and a metering device for the anti-detonant which is controlled by boost pressure and associated with supercharger speed. The pump which delivers the anti-detonant is electrically driven and the current flowing thereto is controlled on the one hand by an override lever whose position ensures that the pump is cut in only when the engine speed is above a determined figure, and on the other hand by boost pressure above a determined value. The pressure at which the anti-detonant is delivered when the pump is operative controls the setting of a stop which permits movement of a lever by which boost can Iii be selected in excess of a determined pressure,

- but when the pump delivering the anti-detonant .mentioned stop controlling boost selection. The accompanying drawing illustrates diagrammaticall the improved apparatus in which the invention isembodied. V

The apparatus as a whole may be said to com- 2. A tank containing the liquid anti-detonant andassociated with it a pump which delivers this liquid under pressurabut is operative only when a determined boost pressure and engine speed are reached.

3. A regulator which determines the flow of the anti-detonant and the pressure at which it is delivered to mingle with the fuel as injected into the engine induction passage.

4. A metering device which is controlled by boost pressure and determines the amount of anti-detonant delivered this metering being associated with supercharger speed.

5. Means associated with the above mentioned regulator which control a device operative to determine the boost pressure which may be selected.

6. An apparatus associated with the boost selection lever by which the richness of the fuel is automatically reduced when the anti-detonant is supplied.

There is no occasion to describe here in detail the fuel injection apparatus which as mentioned above issubstantially in accordance with the description in the specification of British Patent No. 568,643. In that apparatus there is behind the nozzle A, through which the fuel is delivered under pressure into the intake B of the impeller B of the variable speed supercharger of the aircraft motor B an annular chamber C surrounding the fuel delivery pipe A The anti-detcnant is delivered through a pipe C into this chamber C under a pressure which is not less than the pressure of the fuel as delivered to the nozzle A.

. .As the apparatus is primarily for use with an internal combustion engine in an aircraft the tank D containing the liquid anti-detonant is preferprise the following principal parts which are suitan impeller situated and rotated in hat induction passage.

per'square inch, through the pipe E r valve F will lift if the determined delivery presably of a type known as negative G proof being adapted to function irrespective of the attitude ,of the aircraft. A pump E conveniently elecsure is exceeded and then establishes communication through the pipe E with the tank D or the intake B. Thus the pressure loading the relief valve F is that of the spring F and the air behind :the .diaphragm K 20 lbs. to the square inch above the pressure at the fuel and air intake B. I v

The pump E, the motor D of which is conveniently driven by current from a battery E will only deliver anti-detonant liquid when an override lever H has been moved into a'. deterl mined position corresponding to the selection of an engine speed at or above a predetermined figure.

and the lever is connected to the engine gov- .ernor H by a linkage H so that the governor is given'a new setting to permit the engine to run at the higher speed when lever H is so moved. The pump is also permitted to be operative only when the engine boost pressure is at or above a predetermined figure. Movement of the override lever H will close contacts H in the pump motor circuit, .while a capsule J in a chamber J is subjected to boost pressure through a pipe J and this capsule can close contacts J in the pump motor circuit. The abutment J of the capsule is adjustable so that the capsule can be set for the minimum boost pressure at, which the contacts J sh u1d be closed and .th'epump permitted to be operative.

The 'anti-detonant delivered "by the pump'E flows from the separator E through'pipin E ,to-a pressure regulator in a casing K. The'regulater in the casing-comprises a. diaphragm K whichcarries starve K adapted to seat in a port K in a partition K while at the sideof this :partitionfopposite to the diaphragm K is a sec-- ond diaphragm K which is connected to a dou ble-acting valve of which one part K is adapted to shut off the supply of oil under-pressure which .actua'tes certain :parts of the apparatus, this oil' supply coming through the ,pipe L from an engine-driven pump (not shown). The other part K of this valve controls the flow-off of this pressure oil through the pipe L The diaphragm K is loaded by a spring K and by the pressure of the anti-detonant after metering and as t flows to the .fuel nozzle A, this liquid coming through the pipe E into the chamber K The diaphragm K is loaded by a spring K and the chamber K behind the diaphragm is in communication through the pipe G with the pipe .G in which is air at the pressure existantat the intake B. The pipe E through which the anti-detonant is delivered by the pump leads into the chamber K at one 'side of the partition K and the liquid which is allowed to flow according to the setting of the valve K through the port K into -the chamberxKQ is led by the pipe E to the metering device.-

Lever H is moved by the 'pilot When'he wishes the engine to run at such higher speed regulator K enters the central compartment M of the metering device through the pipe E and the main flow of metered liquid takes place through the port in the upper partition M con- 5 trolled by' 'tlie"'valve M and this fiow, which is metered in accordance with boost pressure, takes place through a pipe E which joins the pipe E and in the manner to be described hereunder communicates with the pipe C and the annular .10 chamber .6 around the fuel delivery pipe A The flow of liquid through the port in the lower partition-M which is controlled by the valve M 'is additional to the flow through the port controlled by the valve M and it takes place .15 through a pipe E leading from the lower compartment M and like the pipe E joining the pipeYE In the pipe E is a cock N connected through the lever N and the links and levers N N N N and N to the supercharger gear change lever'O. T-he cock N will be shut when the lever O is-set in-the position 0 for moderate speed, butwill be fully open when the lever O is set in-the positionO for full supercharger speed. The superchargergear change lever O is manuallybpe'ra-ted and is connected up in a known manner as follows. An extension N" of the linke N connects with the operating lever of a three-way cock 0; one way '0' of this cock is connected to the pressure oil supply through a pipe L and lo the other ways 0 and 0 communicate respectively with the moderate speed clutch B and 'the 'full --s,p eed clutch B in the supercharger fchange speed' mechanism B When the lever 0 is in the position-O pressure oil flows through the ways 0 and 0 and causes the moderate speed clutch B toengage. When the lever O Iisf'.the positionQ 'pressure oil flows through thewaysO -and O and causes the full speed clutch *B? to engage. The setting of the regulator'K ensures a small pressure drop across the metering orifices in the partitions M, M and this pressure difference can be accurately set by "adjustmentof the spring K in the regulator K which loads the diaphragm K with the valve K Thus 'asjmentioned the flow of anti-detonant in accordance with moderate supercharger speed is metered by thevalve M in accordance with boost pressure while the flow in accordance with full supercharger speed will be an additional amount i meteredby the valve M the amount being determinedlby the setting of the cock N in correspondence with the position of the lever 0. .Hence the flow through the two ports controlled by the valves M and M takes place when under fullhsupercharger speed conditions.

,The anti-detonant from the metering device M flows by way of the pipe E into a casing P which is vdivided jby a diaphragm P into chambers P andflP 'The diaphragm P functions as a valve 60, ,in.,coh'j 1 nction with an annular projection P in-the chamber JP and thus controls the flow .of anti-deton'ant from the part of the chamber L P within the annular projection P into the part o'fthe chamber 1?? which is outside the annular 5 projection Pt. From the latter part of the chamber P ,'the"anti-detonant passes by Way of the pipe C to the chamber C around the fuel delivery pipe A The diaphragm P is loaded first by aspringl 'F and'by, the action of the operating pressure liquidinth'e system as permitted to flow through the pipe L and act in a cylinder on a plunger P which projects from what may be called "the {back of the diaphragm P Pressure liquid can'drain'from the chamber P at the back of the diaphragm to the intake B-through piping Q of which a branch Q 'also runs to the gland through which passes the spindle M which carries the valves of the metering device. The valve contained in the casing P constitutes in effect a safety device to prevent fuel from fiow ing back from the nozzle A into the anti-detonant system should the supply of anti-detonant fail for any reason.

The sequence of events in the apparatus as so far described is as follows. The pump E builds up the pressure of the anti-detonant liquid in the central chamber K in the regulator K and by acting on the diaphragm K moves the valve K downwards, stopping the flow of. pressure oil or other liquid entering by the piping L. Simultaneously as the valve K moves off its seating the drain L for the pressure liquid is opened, thereby relieving the pressure in the piping system L The liquid anti-detonant under pressure flowing through the piping E the metering device M and the piping E E into the chamber P acts on the diaphragm valve P against the spring P and this valve is lifted and allows the anti-detonant to flow through the piping C and the chamber C to the nozzle A. The diaphragm valve P in effect acts as a static head valve and when it cuts off the supply of anti-detonant, as when the valve P is seated by the pressure of the liquid in the pipin L it serves to prevent the back flow of fuel from the nozzle A into the chamber C and piping C and so into the antidetonant system. Oil leakage from the piping L past the plunger P into the chamber P drains away by the piping Q to the intake B and this piping serves to balance the pressure on the diaphragm P by placing the chamber P in communication with the datum pressure at the intake B.

When the supply of anti-detonant under pressure operating in the central chamber K of the regulator K cuts off the supply of pressure oil through the pipe L, the relief by opening the drain L in thepressure oil system reduces in a cylinder R the pressure of this oil supply on one side of the piston R since the one end of this cylinder is in communication through the piping L with the pressure oil system. The spring 15?, acting on the piston R then moves this piston and a two-armed lever R R to the arm R of which the piston R is connected. On the same pivot R about which the lever R R can turn is a lever R connected with a pilot operated boost selection lever not shown. The boost selection lever actuates a throttle valve in the supercharger intake and thus controls the boost pressure. This arrangement is well known in itself and is therefore not shown in the drawing. The lever R has a tail R which can come into contact with a stop R on the arm R of the lever which is connected to the piston R When the pressure in the piping L is relieved and the piston R able to move into the position in which it is indicated in the drawing, it is possible for the boost lever R to be moved from the position indicated at R, which for example may represent fifteen pounds per square inch boost pressure, into the position R when the boost pressure will be increased to, say, seventeen pounds per square inch. When however the pressure liquid in the piping L is operative, that is to say when for any reason the supply of antidetonant liquid under pressure fails or is cut off and the valve K is lifted, the piston R will be moved to the left, as seen in the drawing, carrying with it the lever R R The stop K will then position B and a decrease in the boost pressure brought about. This arrangement prevents the selection of boost pressure above a determined figure unless the pressure of the anti-detonant as delivered by the pump has been built up sufficiently to enable this liquid to be metered and delivered to the fuel nozzle. This part of the apparatus serves also as a safety device since if the pressure in the delivery pipe from the pump E fails, for example as a result of interrupting the current flowing to the pump, the stop R will obstruct the movement of the lever R and boost selection above the amount represented by the lever R5 when in the position R will be prevented.

The arm R of the lever acted on by the piston R is connected by a link U to a lever U controlling a cock U in the fuel derichment mechanism described hereunder. The supercharger gear change lever O is similarly connected by a link V to a lever V controlling another cock V in this derichmentmechanism.

This fuel derichment is obtained by reducing the pressure drop across the main fuel metering device and is elfected by apparatus which comprises a known construction and arrangement of parts of which the chief features are as follows:

A casing S of suitable shape is divided by a diaphragm S into two chambers S S and in the chamber S is a valve S connected to the diaphragm and controlling the flow through that chamber of fuel which is led thence by the pipe A to the injector nozzle A. The fuel enters the chamber S by a pipe A leading from a metering device to which the fuel is delivered by a pump (not shown) through the main supply pipe A The metering device, of known construction, comprises a sleeve T in which is a port T the sleeve being movable by means not shown, in a casing 'I' in the wall of which is a port T leading to the pipe A A branch A from the main fuel supply pipe A leads to a subsidiary circuit A in which is a centrifugal impeller A and this circuit runs from and returns to the chamber S at one side of the diaphragm S In this circuit is arranged the means by which the fuel derichment is effected. In the piping A through which the fuel is caused to flow by the impeller A to the chamber S is a fixed constriction A and the variable constriction or cock U which through the lever U and the connecting I linkage W is actuated by the lever R by the positioning of which boost selection is controlled. The opening or closing of this cock U varies the pressure in the chamber S at one side of the diaphragm S movement of which controls the actual flow of fuel to the nozzle A. Since the cock U is actuated through the lever R? which is moved or set in accordance with the pressure at which the anti-detonant is supplied, that is the pressure in the chamber K in the regulator K,

derichment of the fuel will occur only when the liquid anti-detonant is flowing at sufficient pressure to ensure the operation of the metering unit M. The pipe A in the supplementary circuit leading from the chamber S to the eye of the impeller A has two branches A and A In the branch A is the cock V actuated by the lever V which is connected by the linkage V to the lever O controlling the supercharger change speed gear, and in this branch there is also an orifice W the area of which can be adjusted by a valve V Openingof the.cock V affects the fuel flow through the pipe A to the impeller A and 7 consequently the pressure in the diaphragm chamber S when the lever O is in the position O for moderate gear ratio in the supercharger drive. In the other branch A of the piping is an orifice V the area of which can be adjusted by a valve V in the same way as the orifice V moderate drive ratio, on the other hand when the gear is set for full speed the flow through the one branch A will be stopped reducing the amount of fuel which the impeller can draw from the chamber S with the result that there will be a pressure rise in that chamber and consequently movement of the diaphragm S which will partially close the valve S controlling the fuel delivery to the nozzle A and thus effect derichment of the fuel supply.

The engine conditions obtaining when antidetonant is supplied with the fuel necessitate an advance in the ignition timing of the order of 6 and this is effected automatically by the following means. In a casing W is a diaphragm W dividing the casing into two chambers W and W and in the chamber W is a spring acting on that side of the diaphragm. On its other side the diaphragm is connected to a piston valve W movable by the diaphragm in a cylinder W and controlling ports W and W in the wall thereof. A cylinder X which is coaxial with the cylinder W is in effect an enlargement at the end of the cylinder W and in this cylinder X is a piston X acted on by a spring X The end of the cylinder X is in communication with the pressure oil piping L so that when pressure exists in this piping it can act on and move the piston X against the spring X and into contact with the end of the valve W moving it against the spring acting on the diaphragm W Piping J 6 in which is boost pressure communicates with the port W in the cylinder W and with the chamber W at one side of the diaphragm W Piping Y leading from the port W in the cylinder W and from the chamber W runs to an ignition control unit Y which is adapted to be actuated by boost pressure and operates automatically to alter the ignition timing of a magneto or coil Y Piping L leads from a port W in the cylinder W and from a port X in the cylinder X and serves to drain away oil from these cylinders. This apparatus operates in the following manner. When anti-detonant is being delivered and the consequent pressure in the chamber K in the regulator K closes the valve K and cuts off the supply of pressure oil from the pipe L, there is a pressure drop in the cylinder X behind the piston X which is then moved by the spring X away from the end of the valve W which can then assume the position in which it is shown in the drawing wherein it has closed the port W. This shuts off the boost pressure from the piping Y with the effect in the ignition control unit Y of automatically advancing the ignition timing to the required extent. On the other hand when the pump delivery of the antidetonant ceases and the pressure in the chamber K in the regulator K drops, the valve K is moved and admits pressure oil again to the system and flowing through the piping L enters the cylinder X and moves the piston X into contact with the end of the valve W which is then moved so as to uncover the port W and allow the passage of boost pressure into the piping Y with the effect in the ignition control unit that the ignition timing is restored to normal. At starting the port W in the cylinder W is uncovered thus ensuring a reduction in the pressure in the piping Y in accordance with normal starting requirements.

What I claim as my invention and desire to secure by Letters Patent is:

1. A system for supplying fuel and a liquid anti-detonant to an internal combustion engine provided with a supercharger in its induction passage, variable speed driving means for driving said supercharger from the engine and a control for setting the speed ratio of said driving means, said system comprising means for delivering a metered quantity of fuel under pressure through a nozzle into the engine induction passage, a pump which when operative delivers antidetonant to said nozzle so that it will mingle with the fuel issuing therefrom, a pressure regulator for regulating the pressure of the antidetonant delivered to said nozzle, a main metering device through which anti-detonant passes on its way to the nozzle and adapted to meter the quantity of anti-detonant passing therethrough in dependence upon the engine boost pressure, an additional anti-detonant metering device for admitting an additional supply of anti-detonant to'said nozzle, and means for rendering said additional metering device operative only when the supercharger driving means is set for driving the supercharger at the highest speed ratio.

2. A fuel and anti-detonant supply system for an internal combustion engine comprising the parts as set out in claim 1 and in which the said pump which delivers the anti-detonant is electrically driven and the supply of current thereto is controlled on the one hand by an override lever whose position ensures that the pump is operative only when the speed of the engine is set between determined limits, and on the other hand by means controlled by engine boost pressure.

3. A fuel and anti-detonant supply system for an internal combustion engine comprising the parts as set out in claim 1 and in which there is a lever by movement of which boost in excess of a determined pressure can be selected, a stop the positioning of which controls the setting of the said lever and thereby the selection of boost pressure, and means whereby when the said pump is operative and delivering anti-detonant the pressure at which the anti-detonant is delivered will control the setting of the said stop so that when the pump is operative the said lever can be moved to select boost in excess of a determined pressure but when the pump is not operative the stop will prevent that boost selecting movement of the said lever.

4. A fuel and anti-detonant supply system for an internal combustion engine comprising the parts as set out in claim 1 and including a pipe system to which liquid under pressure is supplied, a valve serving to shut off the delivery of anti-detonant to'the said fuel injection nozzle, means for actuating this valve by the said pressure liquid, means for selecting boost pressure including means whereby this selection can be affected by the action of the said pressure liquid, means actuated by this pressure liquid for varying the igdetonant in the said regulator. i

5. A fuel and anti-detonant supply system for an internal combustion engine comprising the parts as set out in claim 1 and including'ineans whereby a reduction can be effected in the richness of the fuel supply-to the engine, and m eans whereby the pressure of the anti-detonantas and when delivered by the said pump can bring about the said reduction in the fuel supply.

6. A system for supplying fuel and a liquid anti-detonant to an internal combustion engine provided with a supercharger in its induction passage, variable speed driving means for driv ing said supercharger from the engine and a control for setting the speed ratio of said driving means, said system comprising means for delivering a metered quantity of fuel under pressure through a nozzle into the engine induction passage, a pump which when operative delivers antidetonant to said nozzle so that it will mingle with the fuel issuing therefrom, a pressure regulator for regulating the pressure of the anti-detonant delivered to said nozzle, a main metering device through which anti-detonant passes on its way to the nozzle, an additional metering device in parallel with said main metering device these metering devices being adapted to meter the quantity of anti-detonant passing therethrough in dependence upon the engine boost pressure, means for shutting off the flow of anti-detonant through said additional metering device, and an operative connection between said shut-off means and said control for the supercharger driving means whereby anti-detonant is permitted to flow to the nozzle through said additional metering device only when the supercharger driving means is set for driving the supercharger at the highest speed ratio.

7. A system for supplying fuel and a liquid anti-detonant to an internal combustion engine provided with a supercharger in its induction passage, variable speed driving means for driving said supercharger from the engine and a control for setting the speed ratio of said driving means, said system comprising means for delivering a metered quantity of fuel under pressure through a nozzle into the engine induction passage, means for reducing the supply of fuel through said nozzle, a pump which when operative delivers antidetonant to said nozzle so that it will mingle with the fuel issuing therefrom, means whereby said pump is permitted to be operative only when an override lever is in a position in which the engine speed is set between determined limits and there is a determined boost pressure, a control by movement of which boost in excess of a determined pressure can be selected, a stop the positioning of which limits the setting of said boost selecting control, means whereby when said pump is operative and delivering anti-detonant the pressure at which the anti-detonant is delivered will control the setting of said stop so that when said pump is operative said control can be moved to select boost in excess of the determined pressure but when said pump is not operative the stop will prevent that boost selecting movement of said control, means whereby the setting of said stop to permit selection of a boost pressure in excess of said determined pressure actuates said means for reducing the fuel supply, a pressure regulator for regulating the pressure of the anti-detonant delivered to said nozzle, a main metering device through which anti-detonant passes on its way to the nozzle and adapted to meter the quantity of anti-detonant passing therethrough 'in dependence upon the engine boost pressure, an additional anti-detonant metering device for admitting an additional supply of anti-detonant to said nozzle, and means for rendering said additional metering device operative only when the supercharger driving means is'set for driving the supercharger at the highest speed ratio.

8. A system "for supplying fuel and a liquid anti det'onant to an internal combustion engine provided with a supercharger in its induction passage, variable speed driving means for drivin said supercharger from the engine and a control for setting the speed ratio of said driving means, said system comprising means for delivering a metered quantity of fuel under pressure through a nozzle into the engine induction passage, a pump which when operative delivers anti-detonant to said nozzle so that it will mingle with the fuel issuing therefrom, a pressure regulator for regulating the pressure of the anti-detonant delivered to said nozzle, said pressure regulator comprising a casing, a ported partition dividing said casing into first and second chambers to the first of which anti-detonant is delivered by said pump, a diaphragm constituting a wall of said first chamber, a spring acting on said diaphragm, a valve controlling the supply of a liquid under pressure to'a pipe system, a connection between said diaphragm and said valve, a second diaphragm in said pressure regulator constituting a wall of said second chamber, a spring acting on said diaphragm, a valve connected to said diaphragm and controlling the size of the port in said partition and hence the pressure drop of the antidetonant in passing from the first chamber to the second chamber, a main metering device to which anti-detonant passes from said second chamber on its way to the nozzle and adapted to meter the quantity of anti-detonant passing therethrough in dependence upon the engine boost pressure, an additional anti-detonant metering device for admitting an additional supply of anti-detonant to said nozzle, means for rendering said additional metering device operative only when the supercharger driving means is set for driving the supercharger at the highest speed ratio, and a Valve serving to shut-off the delivery of the anti-detonant to said nozzle actuated in response to the liquid pressure in the said pipe system, whereby said valve is closed when the pressure of the anti-detonant delivered to said pressure regulator falls below a predetermined value.

9. A fuel and anti-detonant supply system for an internal combustion engine comprising the parts as set out in claim 8 in which said metering devices include a casing divided by two partitions into three chambers with a port in each partition, a capsule subjected to boost pressure and carryin a spindle on which are two valves respectively adapted to engage the ports in the said two partitions, piping through which the anti-detonant from the said regulator enters the first and central one of the three said chambers in the metering device with piping leading from the second of these chambers to the said valve serving to shut off the delivery of anti-detonant to the said nozzle, piping leading similarly from the third of the said chambers, a valve in said latter piping from the third chamber with means for actuating this valve in REGINAL HENRY DQUGLA$ QH MBER REFERENCEfi CITED The following references are of record in the file of this patent:

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